The present invention relates to a rotation angle detecting apparatus using a hall element, a signal processing apparatus for the hall element and a throttle valve apparatus for an automobile using the rotation angle detecting apparatus, and preferably relates to an electronic control type throttle valve apparatus provided with a throttle valve driven by a motor.
Conventionally, a non-contact type rotation angle detecting apparatus (that is, a rotation angle sensor) has been known in which magnets are attached to a rotation shaft and the rotation angle of the rotation shaft is detected in cooperation with the magnets and hall elements disposed at the periphery of the rotation shaft.
In such a kind of the rotation angle detecting apparatus, it is known to constitute the hall elements and a circuit (a zero span adjustment circuit) for performing zero-span adjustment of the outputs of the hall elements and/or a circuit (a temperature compensation circuit) for compensating temperature drift of the hall elements as a single semiconductor package (chip) thereby to enhance the function of the sensor. Such a configuration is generally known as a hall IC.
For example, JP-A-8-68606 discloses the technique in which as a sensing unit for detecting a rotation angle, an EPROM and a register constituting an amplifier circuit and an adjustment circuit etc. are integrated together with a magnetic sensitive element formed by hall elements thereby to constitute a single chip.
Further, JP-A-2000-74613 discloses the technique that in a throttle valve sensor, a hall element generates a hall voltage in response to magnetic flux density changed in accordance with the opening degree of the throttle valve and an IC receives the hall voltage thereby to perform various kinds of processing such as temperature characteristic compensation.